polyfill div_ceil

Author: xtqqczze

src/buffer.rs

@@ -427,7 +427,8 @@ impl NaiveBuffer {
     /// Legendre's phi function, used as a helper function for [`Self::prime_pi`]
     pub fn prime_phi(&mut self, x: u64, a: usize, cache: &mut LruCache<(u64, usize), u64>) -> u64 {
         if a == 1 {
-            return (x + 1) / 2;
+            // TODO(MSRV>=1.73): feature(int_roundings1): use div_ceil
+            return crate::util::div_ceil_u64(x, 2);
         }
         if let Some(v) = cache.get(&(x, a)) {
             return *v;

src/lib.rs

@@ -74,6 +74,7 @@ mod primality;
 mod rand;
 mod tables;
 mod traits;
+mod util;
 
 pub use traits::*;
 pub mod detail {

src/util.rs

@@ -0,0 +1,9 @@
+pub const fn div_ceil_u64(lhs: u64, rhs: u64) -> u64 {
+    let d = lhs / rhs;
+    let r = lhs % rhs;
+    if r > 0 {
+        d + 1
+    } else {
+        d
+    }
+}